New method of current control for LCL-interfaced grid-connected three phase voltage source inverter

Abstract

This paper presents an approach for the connection of a photovoltaic generator to the utility grid. A theoretical analysis, modelling, controlling and a simulation of a grid connected photovoltaic system using an output LCL filter are described in detail. In order to reduce the complexity of the system, a linear voltage and current controllers have been developed for a three phase grid connected inverter. Those controllers simultaneously regulate the dc link voltage (the photovoltaic power is delivered to the grid) and the current injected to the grid (to operate at unity power factor). The simulation results show the proposed methods work properly. Moreover they show that the control performance and dynamic behaviour of the inverter-LCL-grid combination. Simulation results show that the output LCL filter installed at the inverter output offer high harmonic attenuation.

Keywords

• lcl filter
• inverter
• grid
• controller
• modelling